In recent years, there has been developed an air conditioning system which is configured to independently cool and heat a plurality of zones with a vehicle room. For example, there has been developed and used a three-zone-type air conditioning system which is configured to independently cool and heat a driver seat zone, a front passenger seat zone and a rear seat zone of a vehicle room.
In the three-zone-type air conditioning system, as illustrated in FIGS. 1 and 2, a driver seat path 12, a front passenger seat path 14 and a rear seat path 16 are formed within an air conditioner case 10. Temperature doors 20, 22 and 24 are installed in the driver seat path 12, the front passenger seat path 14 and the rear seat path 16, respectively. The temperatures of an air supplied to a driver seat zone, a front passenger seat zone and a rear seat zone are independently controlled by independently controlling the temperature doors 20, 22 and 24. This makes it possible to independently cool and heat the driver seat zone, the front passenger seat zone and the rear seat zone.
As illustrated in FIG. 2, the rear seat temperature door 24 typically includes a first rear seat temperature door 24a installed in the rear seat path 16 at the downstream side of an evaporator 30 and a second rear seat temperature door 24b installed in the rear seat path 16 at the downstream side of a heater core 32.
The first and second rear seat temperature doors 24a and 24b are operated in cooperation with each other to control the temperature of the air blown toward the rear seat path 16, thereby adjusting the temperature of the air supplied to the rear seat zone.
The three-zone-type air conditioning system further includes an auxiliary blower 40 installed in the rear seat path 16. Unlike a main blower 11 for drawing an air existing outside the air conditioner case 10, the auxiliary blower 40 is configured to draw an air existing within the air conditioner case 10. The auxiliary blower 40 further increases the volume and pressure of the air blown along the rear seat path 16 after passing through the evaporator 30 and the heater core 32, thereby increasing the volume and pressure of the air blown toward the rear seat zone. This makes it possible to enhance the cooling and heating performance of the rear seat zone.
In the air conditioning system of the related art, if the air introduced into the rear seat path 16 has a high temperature, namely if the hot air passed through the heater core 32 is introduced into the rear seat path 16, the auxiliary blower 40 is continuously exposed to the hot air. Due to the continuous exposure of the auxiliary blower 40 to the hot air, the auxiliary blower 40 may be thermally deformed or damaged. This may lead to a problem in that the blowing performance of the auxiliary blower 40 is reduced and a blowing noise is generated.
In particular, when the rotation speed of the auxiliary blower 40 is high, the auxiliary blower 40 may be overheated. If the overheating of the auxiliary blower 40 and the contact of the auxiliary blower 40 with the hot air occur at the same time, the auxiliary blower 40 may undergo severe thermal deformation and damage.
For example, when the rear seat zone is controlled in a vent mode and a bi-level mode, the auxiliary blower 40 is rotated faster than in a floor mode. In this case, the auxiliary blower 40 may be overheated. When making contact with the hot air, the overheated auxiliary blower 40 may undergo severe thermal deformation and damage.
This may lead to a problem in that the blowing performance of the auxiliary blower 40 is reduced and a blowing noise is generated. Thus, the pleasantness in the rear seat zone may be sharply reduced.